Navigation instrument



FIG. 1 is a top perspective view of the navigation instrument;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a rear plan view thereof; and,

FIG. 5 is a top plan view of an alternative configuration of the navigation instrument.

Elements shown in broken lines are provided for illustrative purposes but form no part of the claimed invention. 

CLAIM The ornamental design for a navigation instrument, as shown and described. 